COMPARISON AND SELECTION OF ENGINEERING GEOLOGY AND ROUTES ACROSS EAST AFRICAN RIFT VALLEY—TAKE THE NAIROBI-MALABAR RAILWAY FOR EXAMPLE

The Nairobi-Malabar railway project is an important part of the "northern corridor" of East Africa. It is the trunk line of economic development in landlocked African countries. The railway line works pass through the rift valley. The volcanic landform, the fault belt and the tension fracture are extremely development. However, there is a lack of research data on railway construction in the rift valley. To study railway lines through the rift valley, firstly, this paper introduces the topography, landform, development mechanism and regional fault distribution of the east African rift valley, and then formulates three major railway routes through the east African rift valley based on the economic control points along the railway. We had compared the terrain and landform traversed by the three major routes, the stratum, fault and ground fractures, the earthquake and volcanic developments, and the adverse geological disasters. Finally, the investment, advantages and disadvantages of each route had been compared, and finally the southern route scheme was recommended. The scheme of the route was approved and adopted by the Kenyan government. At present, the Nairobi Malaba railway is in trial operation, and the practice shows that the selection of the rift section of Nairobi-Malabar railway is relatively successful, which can provide reference for similar projects.